JPS6248004A - Wire dot head - Google Patents

Abstract

PURPOSE:To facilitate the soldering on a printed circuit board by a method wherein the end of a coil is formed in a cylindrical shape so as to make it easy to handle the end and to pass through the throughhole made on a yoke and heat dissipation plate. CONSTITUTION:In a wire dot head which has an armature on whose end one end of wire is fixed, and the armatures are selectively driven by means of electromagnets to perform dot recording, the end 27 of a coil 7 consisting an electromagnet is formed in a cylindrical shape. The end 27 of the coil 7 is formed in a cylindrical shape, and the axial direction of the end 27 is pallarel to the axial direction of the coil 7. The end 28 of the coil is formed in a cylindri cal shape. However, its axial direction perpendicularly intersects the axial direction of the coil 7. With such a construction adopted, both ends 27 and 28 are formed in cylindrical shapes and have specified diameters, being easily handled with rigidity of the structure. Thus it is easy to perform the work to mount it through the throughhole made on a yoke or heat dissipation plate and it is also made easy to solder it on a printed circuit board, facilitating automatic assembly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application in Junior Business] The present invention relates to a wire dot head, and more particularly to a wire dot head equipped with a large number of wires.

[Prior Art] In order to print characters etc. using dots, as shown in FIG. 2, a matrix structure of mXn dots is formed, and P! The desired printing can be performed by moving n wires arranged in the vertical direction at a pitch of P2, shifting them m times, and driving the wires for each shift.

The conventional structure of a wire dot head for performing such dot printing is shown in FIGS. 3 to 6. Figures 3 to 6
In the figure, the reference numeral 1 indicates a tip guide, which is fixed to the intermediate guide 2. The intermediate guide 2 is formed with a notch 2a for a screw to be attached to a carriage (not shown).

A flexible printed circuit board 3 that is integrated with a heat dissipation plate 4 is arranged behind the intermediate guide 2.

The heat dissipation plate 4 also serves as a spacer between the flexible printed circuit board 3 and the yoke 5 formed in the shape of an elliptical cylinder, and transmits the heat of the yoke 5 to a back halter, which will be described later.
A material with excellent thermal conductivity such as aluminum with a thickness of about 2 mm is selected.

A plurality of cores 6 are fitted into the yoke 5, and a pobbin 8 around which a coil 7 is wound is attached to the core 6.

Two terminals 8a are protruded from the bobbin 8, and the winding start and winding end portions of the coil 7 are fixed to these by soldering. The terminal 8a is connected to the yoke 5. The solder is fixed to the flexible printed circuit board 3 side through the heat dissipation plate 4.

On the other hand, the reference numeral 9 denotes a rear guide, which is formed into a cylindrical shape as a whole, and is connected to the yoke 5° heat dissipation plate 4.
．． The intermediate guide 2 passes through the flexible printed circuit board 3.
It is placed in a state where it is fitted inside.

One end of a return spring 10 is fixed to the rear end of this rear guide 9. On the other hand, the open end of the rear end of the yoke 5 is closed by an auxiliary yoke 11. A circular opening is formed in the center of the auxiliary yoke 11, and the rear end of the rear guide 9 corresponds to this opening.

Further, a boss 8b protruding from the rear end side of the pobbin 8 is fitted into a through hole formed in the auxiliary yoke 11 and protrudes rearward, and the rear end portion of the armature 14 is mated.

The number of armatures 14 is the same as the number of wires 22, and a plunger 13 is provided in the middle thereof.

Further, a spacer 12 is arranged between the auxiliary yoke 11 and the armature 14.

This spacer 12 is connected to the auxiliary yoke 11 and the armature 14.
This is provided to prevent wear due to contact with the auxiliary yoke 11 and destabilization of the pressure movement of the armature 14 due to residual magnetism of the auxiliary yoke 11, which is a problem when forming a closed magnetic circuit.

As shown in FIG. 6, a plurality of armatures 14 are arranged radially, and the proximal end of the wire 22 is fixed to the distal end thereof. The return spring 10 is installed between the free end of the armature 14 and the rear end of the rear guide 9, and the return spring 1O causes the armature 14 to
The free end side is always given a force in a direction away from the rear end of the rear guide 9.

On the other hand, a stopper 15 is arranged at the rear of the armature 14 and faces a position where it can come into contact with the free end side of the armature 14. This stopper 15 is fitted into the stopper holder 16, and the tip of each node of the radially formed armature presser spring 17 presses the base end side of the armature 14 against the auxiliary yoke 11. It has become.

By the way, a damper 18 is arranged behind the armature presser spring 17. This damper 18 is made of a material with high specific gravity such as lead, and the washer 19. It is arranged in contact with a back holder 21 via a spring washer 20.

Since the /header holder 21 has a large effect on the heat dissipation of the head, the surface area of the header holder 21 is made as large as possible, and a large number of fins are formed on the outside as shown in FIG.

This back holder 21 has screws 23 attached to the intermediate guide 2.
It is fixed in place and covers the armature and yoke as a whole.

Further, the washer 19 prevents the spring washer 20 from biting into the damper 18.

Further, the wire 22 is attached to each guide, wire 1, 2, . . . to prevent buckling.
9, the plurality of wires 22 are gradually guided in a vertical line along these guides, and are completely arranged in a vertical line within the tip guide 1.

In order to print based on such a structure, when the coil 7 is energized according to the printing command, the yoke 5. Auxiliary yoke 11. Plunger 13. Since a closed magnetic path is formed by the core 6, the plunger 13 is attracted toward the core 6, and the armature 14 resists the elastic force of the return spring 10 to cause the wire 22 to protrude a predetermined distance from the tip guide l. The wire 22 prints dots on the paper via an ink ribbon (not shown).

By the way, in conventional wire dot heads having the above-described structure, the coil 7 is often wound around a coil bobbin, and when a coil bobbin is used, it is easy to assemble automatically, but it is difficult to drive the wire. The coil bobbin is not involved in any way, which increases the cost and becomes an obstacle to making the wire dot head more compact.

Therefore, as shown in FIG. 7, a structure in which the coil 7 is formed into a cylindrical shape and does not use a coil bobbin has been proposed.

The winding start and winding end 7a of this cylindrical coil 7 are connected to a yoke 5. It penetrates through the heat dissipation plate 4 and is soldered to the printed circuit board 3 side.

The cylindrical coil 7 is fixed to the yoke 5 with an epoxy resin adhesive 24 to prevent disconnection due to head vibration, and a thermistor 25 is installed to detect the temperature of the coil 7 to prevent the coil 7 from seizing. is similarly embedded in the vicinity of the coil 7 with adhesive 24.

A boss 8b is protruded from the auxiliary yoke 11 in one-to-one correspondence with the core 6, and the rear end of the armature 14 is fitted into the boss 8b.

[Problems to be Solved by the Invention] However, if the above structure is adopted, there is an advantage that a coil bobbin is not used and costs can be reduced, but the end 7a of the coil does not pass through the yoke 5 and the heat sink plate 4. This has the drawback that soldering to the printed circuit board 3 side is extremely difficult and complicated work, which becomes an obstacle to automatic assembly.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention employs a structure in which the ends of the coils are formed into a cylindrical shape.

[Function] When the structure described above is adopted, the end of the coil is formed into a cylindrical shape instead of a thin wire, making it extremely easy to handle and making it easier to penetrate through holes formed in the yoke and heat dissipation plate. Easier to solder to printed circuit board.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

1(A) and 1(B) illustrate different embodiments of the present invention, and in the embodiment shown in FIG. 1(A), the coil 7 is formed using, for example, a self-welding conducting wire. It is formed into a cylindrical shape, and its end 27 is formed into a cylindrical shape.

In the structure shown in FIG. 1(A), the axial direction of the terminal 27 is parallel to the axial direction of the coil 7.

Further, in the embodiment shown in FIG. 1(B), the end 28 of the coil is similarly formed in a cylindrical shape, but the axial direction thereof is perpendicular to the axial direction of the coil 7.

If the structure described above is adopted, any terminal 27.2
8 is also cylindrical in shape, has a predetermined diameter, and is strong and easy to handle.

Therefore, it is easy to attach the device by penetrating the through hole formed in the yoke or the heat dissipation plate, and it is also easy to solder it to the printed circuit board.

Furthermore, since it is easy to handle, it is extremely easy to automate assembly.

[Effect] As is clear from the above description, according to the present invention, a structure is adopted in which the end of the cylindrical coil is formed into a cylindrical shape smaller in diameter than the coil itself.
The terminal is strong and easy to handle, it is easy to pass through the yoke and heat dissipation plate, it is easy to solder to a flexible printed circuit board, and it is easy to automate assembly work.

[Brief explanation of the drawing]

FIGS. 1A and 1B are perspective views of coils explaining different embodiments of the present invention, FIGS. 2 to 6 illustrate conventional structures, and FIG. 2 is a dot matrix coil. 3 is a longitudinal cross-sectional side view of the wire dot head, FIG. 4 is an exploded perspective view of the wire dot head, FIG. 5 is a view taken along the line A-A in FIG. 3, and FIG. The BB line arrow view in the figure and FIG. 7 are enlarged sectional views of the main parts.

Claims (1)

[Claims] In a wire dot head, which has an armature at one end to which the base end of each wire is fixed, and which records dots by selectively driving these armatures via electromagnets, the terminals of the coils constituting the electromagnets are A wire dot head characterized by being formed into a cylindrical shape.